This invention relates to agricultural tractors and in particular to a method and apparatus for extending or stretching the frame of a tractor whereby an agricultural implement may be attached between the front and rear wheels of the tractor.
The present invention is especially useful in ridge till farming of row crops wherein the crops are planted on ridges. The ridge till farming method has become increasingly popular because it enables farmers to grow crops without conventional plowing to prepare the soil for planting thereby saving substantial amounts of both fuel and labor. Furthermore, the ridge till method is advantageous because it reduces soil erosion and soil loss, and reduces the run-off of fertilizers, pesticides, and moisture from the fields.
While tractors have been provided in the past which permitted side mounting of cultivators, planters, and similar agricultural implements, the most common method of attaching agricultural implements to tractors has been to attach the implements behind the tractor. This method of attachment has been satisfactory with conventional farming techniques. However, this method of attaching agricultural implements presents a number of problems when the ridge till method of farming is employed. In the ridge till method, the ridges are normally approximately thirty (30) inches apart and six to eight (6-8) inches high. It is very important for the tractor operator to properly align the agricultural implement, such as a planter or cultivator, with the ridges. If a conventional tractor with a rear mounted agricultural implement is used, the operator must periodically look backwards to assure that the implement is properly aligned with the ridges. Furthermore, the operator must continually look at the tractor front wheels to assure that they are properly aligned with the valleys between the ridges. Thus, the operator must continually swivel his head back and forth. This is rather difficult to do and results in increased fatigue for the tractor operator. More importantly, by mounting the implement behind the tractor, control over the alignment of the implement and adjustments in alignment are difficult to achieve due to the lack of visibility. Normally the operator is at least six (6) feet off the ground and is surrounded by the cab frame. It is therefore difficult for him to look backward and continually assure that proper alignment of the agricultural implement with the ridges is being achieved, thus resulting in poor control over implement alignment. Control is especially important in ridge till planting as misalignment affects the seed planting depth and therefore adversely affects crop yields. Furthermore, control in ridge till cultivating is very important as misalignment of the cultivator may result in root pruning, or even total destruction of the plants. While mounting an agricultural implement ahead of the tractor operator is particularly useful in the ridge till method of farming, such a mounting arrangement would also be advantageous for use in conventional farming methods. It is therefore desired to provide a method for mounting an agricultural implement ahead of the tractor operator to improve visibility by the operator and control over the implement.
Prior art tractors have also been provided which permitted mounting of farm implements in front of the front wheels. However, this implement mounting arrangement results in loss of control as there is an increase in the lateral distance which the implement moves for a given amount of turning adjustment of the tractor front wheels. Thus the operator will tend to overadjust the implement so that alignment of the implement with the ridges is difficult to maintain. Furthermore, due to the large size of agricultural implements, the amount of weight which would be cantilevered from the tractor front wheels in such a mounting arrangement is substantial, thereby resulting in further loss of control over the implement and its alignment with the ridges. It is therefore desired, for improved control of an agricultural implement and for better distribution of the weight of an agricultural implement, to provide a tractor to which an agricultural implement may be mounted between the front and rear wheels of the tractor. In such an arrangement, control over the implement is improved and the weight of the implement is distributed between the front wheels and the rear wheels of the tractor.
Ridge till tractors have also been proposed wherein the frame of the tractor is quite long and is quite high above the ground so that an agricultural implement may be mounted between the tractor front and rear wheels. Such ridge till tractors have been proposed to improve control and visibility of the agricultural implement. However, such proposed tractors are very specialized and would only be useful for mounting agricultural implements between the tractor front and rear wheels and would be unsuited for rear mounting of agricultural implements. Since various agricultural implements are suitable for rear mounting only and cannot be mounted between the tractor front and rear wheels, a farmer would therefore need to purchase a specialized ridge till tractor as well as a conventional tractor for pulling certain agricultural implements such as fertilizing implements, grain carts, plows, and the like. The expense involved for a farmer in purchasing and maintaining a ridge till tractor would thus be quite high. For instance, at today's prices, it is estimated that the cost of a specialized ridge till tractor would be in excess of fifty thousand dollars ($50,000). Furthermore, by necessitating the purchase of two (2) tractors, namely a conventional tractor and a specialized ridge till tractor, a farmer would also need to provide storage space for the extra tractor and would incur added maintenance costs.
It is therefore desired to provide a method and apparatus for converting a conventional tractor to a tractor wherein a farm implement may be mounted between the tractor front and rear wheels so that farmers do not need to purchase a specialized ridge till tractor. It is furthermore desired to provide a method and apparatus for extending or stretching the frame of a conventional tractor whereby a farmer may adapt his conventional tractor to a ridge till tractor and may convert the tractor back to a conventional tractor when desired.
Still another problem which has been encountered in ridge till farming with rear mounted agricultural implements is that, on hilly slopes when the tractor tends to slide, any adjustments which the tractor operator makes for this sliding movement will be counterproductive in aligning the agricultural implement with the ridges. It is therefore desired to provide a tractor wherein the agricultural implement is mounted between the front and rear wheels so that adjustments for the sliding movements of the tractor on hilly slopes will not adversely affect alignment of the agricultural implement. Accordingly, it is desired to provide an articulated extended frame for extending the frame of a cantilevered tractor to improve the "crabbing" ability of the extended tractor while maintaining the alignment of the agricultural implement with the ridges.